Thread protector



April 19, 1949. UNKE 2,467,709

THREAD PROTECTOR Filed April 5, 1947' 2 Sheets-Sheet l III'II'I II II H62 INVENTOR.

' HERMAN H. U/vmr H T TORIVE ya i 9 April 19, 1949. I

H. A. UNKE THREAD PROTECTOR 2 Sheets-Sheet 2 Filed April 5 1947 INVENTOR. HERMHN H. UNKE BY Mn ,ZWXZMS Ww HTTokNEYS I Patented Apr. 19, 1949 UNITED STATES PATENT OFFICE THREAD PROT-EGTO-R Herman A. Unke, Parma Heights, Ohio Application .April- 3, 1947, Serial No.- 739,242

'11 Claims.

This invention relates to thread protectors of the kind used on the ends of pipes or other threaded members for protecting the threads during handling and shipment. Since protectors of this kind are used very extensively on pipes, .the threaded member is hereinafter referred to as a pipe or pipe-end but this is merely for convenience of description and is not intended to limit the improved protector to this particular use.

. objectof the invention is to provide a thread protector of this character which can be economically manufactured and which will be stron and durable and not likely to become disengaged from the pipe to which it has been applied.

Another object is to provide an improved thread protector comprising a sleeve and a strip or insert having longitudinal ridges thereon, the strip being assembled with the sleeve to extend substantially circumferentially along or adjacent the wall thereof so that the ridges form the screw threads of the protector.

Still another object is to provide a thread protector of the character mentioned, in which one .end only of the thread strip is anchored to the sleeve so that the strip will be capable of selfadjustment and will automatically wrap around and tighten itself against the threads of the pipe while the protector is being screwed thereon.

A further object is to provide an improved thread protector of this kind in which shoulder means on the sleeve holds the thread strip with its ends in offset relation so that its ridges form the helical screw threads.

Yet another object is to provide a thread-protector of this character in which the thread strip is resilient in character and of a shape such that portions thereof will be pressed against and grip the pipe for retaining the protector thereon.

It is also an object of this invention to provide a novel construction and method in which a sheet metal strip having spaced shoulder elements thereon is curved to sleeve shape, and .a second strip having longitudinal ridges thereon is curved to annular shape and assembled with thesleeve so that the ridges of the second strip form screw threads for the sleeve.

Other'objects and advantages Of the invention will be apparent from the following description and the accompanying sheets of drawings in which-- Fig. 1 is an end view of a thread protector embodying the present invention;

Fig. 2 is a longitudinal sectional view taken therethrough on line 22 :of Fig. 1.;

Fig. '3 is a fragmentary view showing the pro- 2 tector applied to a pipe-end, .portionsof the pro teeter being shown in elevation and other porti-ons beingshown in section;

Fig. i is a plan view showing .a strip of sheet metal used in iorming the sleeve of the improved thread protector; v

.Fig. 5 is an edge view of the strip with apor tion thereof shown in section; V I

.Fig. 6 is a plan view showing the longitudinally ridged strip from which the thread insert is formedand Fig. '7 is a sectional view on a larger scaletaken through the thread strip as indicated by line 1- 1 of.Fig..6.

:As one practical embodiment of the invention Figs. 1 2 and 3 show a thread protector ill. comprising a tubular body orsleeve :I-TI and a threadforming strip or insert [-2 assembled with such body or sleeve. Fig. 3 shows the protector T0 applied to the threaded end portion .of a pipe P. As further explained herein-after, the insert 12 has longitudinal ridges thereon which form the helical screw threads 13 of the sleeve. L l. this instance the thread-forming strip t2 shown in an assembled position inside the sleeve ill so as to provide the screw threads 1-3 internally or the latterf but it should be understood that this strip could be mounted on the outside of the sleeve if desired. so as to form external threads thereon.

'The sleeve 1'! is substantially circular in crosssectional shape andmay have :any desired diameter and length appropriate for the pipe-end to which the protector i0 is to be applied. One end of the sleeve is open to admit the threaded pipeend P and the other end has an inturned annular .fiange 1'4 which is engaged by and protects the extreme end of the pipe. The sleeve is provided with shoulder means .for mounting the insert l2 therein and, in this instance, the shoulder means comprises axially spaced groups or rows of lugs f5 and HS. Each such row is formed by lugs spaced circumferentia'lly around the sleeve and 'both rows are inclined so as, to extend substantially lhelically .around the wall .of the sleeve to correspond with the pitch or slope of the threads of the pipe-end P. The axial spacing of the rows of lugs is such that the insert .12, will be received with a small clearance .therebetween and with each row forming an interrupted shoulder which is adapted to be engaged b one edge of theinsert.

The sleeve l I .can be formed from a iflat strip or material such as the sheet metal strip .|.8' show-nin Figs. sand 5. v Thestripiscurvedrto an--- nularshape orsleeve form and its meeting ends are subsequently connected together by the weld I9. The sleeve can also be formed so as to initially have a circular or annular shape, such as by cutting sections from tubular stock or by drawing operations performed on sheet metal blanks. In the case of thread protectors for use on pipes of relatively large diameter it is much more economical to construct the sleeve from the flat sheet metal strip I8.

When the sleeve H is constructed from the flat sheet metal strip I8 the lugs I and I6 are preferably formed on the strip before it is curved to annular shape and Figs. 4 and 5 show the fiat strip as having these lugs formed thereon. The lugs I5 and I6 can be formed on the strip I8 by a suitable punching operation in which integral portions are partially sheared from the strip and are displaced out of the plane thereof. This causes the lugs to stand out on one side of the strip while leaving slot-like recesses I5a and I6a in the opposite side of the strip. As shown in Fig. 4 the lugs I5 and I6 are located in progressively offset relation along the strip I8 so that when the strip is curved to sleeve shape the rows of lugs will extend substantially helically of the sleeve at a slope or pitch corresponding substantially with the slope or pitch of the threads I3 of the complete protector. The strip I8 preferably also has openings 26 punched therein at points near its ends and which will lie adjacent to but on opposite sides of the weld I9. These openings are used for anchoring one end of the thread insert I2 to the sleeve, as explained hereinafter.

Although the lugs I5 and I6 have been described above as being formed on the flat strip I8 prior to it being curved to sleeve shape, it should be understood that these lugs can, if desired, be formed after the strip has been shaped into a sleeve. Likewise when the sleeve is constructed with an initially cylindrical shape by cutting sections from tubular stock or by sheet metal drawing operations, the lugs are formed directly on the wall of the sleeve.

The thread insert I2 is formed from a sheet metal strip 2| which has a group of the longitudinal thread ridges I3 on one side thereof. These ridges have a tapered or convexed crosssectional shape corresponding substantially with screw threads and are separated by longitudinal spaces I3a of convergent cross-sectional shape corresponding with thread grooves. The ridges I3 can be formed on the strip 2I by any suitable metal-working operation such as by subjecting the strip to rolling between appropriate die rolls.

During the rolling operation the ridges I3 are formed by metal which is displaced from the wall of the strip by the formation of the longitudinal grooves 22 in the back of the strip.

The insert strip I2 is of a width to provide a suitable number of the ridges I3 such as the five ridges shown in this instance. The strip also an appropriate length which is somewhat less than the circumference of the sleeve II so that when the strip is curved to annular shape and assembled with the sleeve it will extend circumferentially along the wall thereof and its ends I2a and I 2b will be disposed in adjacently opposed relation to each other.

When the insert strip I2 is mounted interiorly of the sleeve, as shown in Figs. 1 and 2, it is curved to an annular shape with the ridges I3 extending around the inside thereof and the strip isthen thrust into the sleeve I I so as to snap into place between the helically extending rows of lugs I5 and I6. When the strip I2 has been thus assembled in the sleeve II its ends I2a and I2!) will be held in axially offset relation, as shown in Fig. 2, with the ridges I 3 ofiset at this point a distance substantially equal to the pitch or spacing of two adjacent ridges. The strip is retained in this position in the sleeve by the rows of lugs I5 and I6 with the ridges I3 of the strip forming the helical screw threads of the protector I0.

An anchoring means is provided between the rows of lugs I5 and I6 for connecting the insert I2 with the sleeve I I. This anchoring means may be any suitable type of connecting device, but preferably as here shown, comprises Welds 23 located in the openings 20 of the sleeve and which anchor the insert to the latter. It will be observed from Figs. 1 and 2 that the welds 23 connect only the end I2a of the insert I2 with the sleeve II while the remaining portion of the insert, including the end I2b, is unanchored and is capable of some shifting relative to the sleeve while held therein by the rows of lugs I5 and I6.

When the sleeve II and the insert I2 are formed by curving the strips I8 and 2I to annular form as explained above they are not usually truly circular in shape but may be somewhat outof-round. This slightly out-of-round condition is an advantage rather than a disadvantage in a thread protector of this kind because it causes the protector to grip the pipe-end in a manner which permits the protector to be screwed on or off but which effectively prevents the protector from working loose. The out-of-round condition just mention is due in part, to the springback eifect of the metal of the strips I8 and 2| and the different amounts of such spring-back effect occurring in difl'erent portions of the strips, when they are curved to annular shape. In Figs. 1 and 2 the out-of-round shape of the insert I2 can be seen since this condition causes portions of the insert to be spaced somewhat from the wall of the sleeve II as indicated at 24 and 25 while other portions of the insert engage or lie against the sleeve.

In the protector ID here shown the threads I3 formed by the ridges of the insert I2 are righthand threads and the ends Ho and H12 of the insert are, respectively, the leading and trailing ends for rotation of the protector in a direction to screw the same onto the threaded pipe-end P. During the operation of screwing the protector onto the pipe the ridges of the anchored leading end I 2a of the insert engage and follow the screw threads of the pipe. The remainder of the insert I2 is thus pulled around the threaded portion of the pipe by the anchored end I M. and this causes the resilient insert strip to wrap itself around the threaded portion of the pipe with an action tending to tighten the insert against the pipe. This wrapping or tightening action of the insert I2 causes the same to readily adjust itself to the pipe and also causes the threads I3 to engage more closely in the thread grooves of the pipe so that the protector can be screwed on with a more positive action and with less likelihood of having the threads of the protector jump or cross the threads of the pipe to which it is being applied. It is important to also note that the clearance between the insert and the lugs I5 and I6 permits the insert to shift and adjust itself to the pipe-end while being applied thereto, and that the irregularities or out-of-round condition of the insert causes the same to grip the pipe.

The end flange I4 can be formed on the sleeve I I at any desired point in the manufacturing operation, but when the sleeve is formed from the fiat strip l8, this-flange ispreferably formed on the sleeve after the strip has been curved to sleeve shape and after the ends of the strip have been connected by the weld l9. Although the ends of the strip l8 can be welded together prior to the mounting of th insert l2 in the sleeve, it is desirable" to form the weld I9 after the insert has been engaged inplace between the rows oflugs l-i' and l G-because the advantage is then obtained that this weld will also serve as a part of the anchoring means for the insert. As shown in the drawings the position of the insert in the sleeve II is such that the leading end [2a underlies the openings 20 and spans the joint formed by the weld I9.

From the foregoing description and the accompanying drawings it will now be readily understood that this invention provides an improved thread protector which is of simple form but which is nevertheless very rugged and durable, and is not likely to become disengaged from the pipe-end or other threaded member to which it is applied. It will also be seen that since the thread of the protector is formed by a ridged strip having one end only anchored to the sleeve of the protector, suchthread-forming strip will be capable of limited shifting relative to the sleeve and will accommodate itself to the pipe and will tighten itself against the thread of t e pipe while the protector is being screwed thereon.

Although the improved thread protector has been illustrated and described herein to a detailed extent, it will be understood, of course, that the invention is not to be regarded as limited correspondingly in scope, but includes all variations coming within the terms of the appended claims.

Having thus described my invention, I claim:

1. A thread protector comprising, a sleeve, a resilient strip extending substantially circumferen" tially adjacent the wall of said sleeve, said strip having spaced ridges extending longitudinally thereof, means holding said strip with the ends thereof in offset relation so that said ridges form screw threads, and connecting means substantially rigidly connecting one end of said strip to the sleeve while the other end remains free and is capable of limited floating movement relative to said sleeve.

2. A thread protector comp-rising, a metal sleeve, a strip extending substantially circumferentially along the wall of said sleeve and lying thereagainst, said strip having spaced ridges extending longitudinally thereof, means providing shoulders spaced apart axially of said sleeve and cooperating with said strip for holding the same in a position such that said ridges form screw threads, and a weld anchoring one end of said strip to said sleeve while other portions of the strip are capable of limited shifting between said shoulders and relative to the wall of the sleeve.

3. A thread protector comprising, a metal sleeve, a strip extending substantially circumferentially adjacent the wall of said sleeve, said strip having spaced ridges extending longitudinally thereof, and substantially helically extending rows of lugs on said sleeve and engaging edge portions of said strip for holding the latter in a position such that said ridges form screw threads.

4. A thread protector comprising, a metal sleeve, a metal strip having longitudinal ridges thereon, said strip being curved to annular shape and retained in said sleeve and having leading and trailing ends offset from each other axially of the sleeve so that said ridges form screw threads, and means anchoring. said leading endt onlyto said sleeve while the-trailingiend remains free andis capable of limit'ed shiftingmadiallyand;

axially relative to-said sleeve.

5. A thread protector for application to the threaded portion of a member comprising, azmetal sleeve, anda resilient metal strip having longitudinal ridges thereon and extending Substantial-i ly circumferentially' in said sleeve so that said ridges form screw threads, said strip having one end only anchored to said sleeve while the other end remains free for limited floating movement relative to the sleeve so as to be capable of selfalignment with the threads of said member when the protector is screwed thereon.

6. A thread protector of the character described comprising, a metal sleeve, a resilient metal strip extending substantially ciroumferentially around the inside of the sleeve and lying thereagainst, said strip having substantially parallel ridges extending longitudinally thereof, and substantially helically extending shoulder means in said sleeve and providing axially spaced shoulders therein, said shoulders being disposed so as to engage edge portions of the strip for holding the same in a position such that said ridges form screw threads.

7. A thread protector of the character described comprising, a metal sleeve, a resilient metal strip extending substantially circumferentially around the inside of the sleeve and lying thereagainst, said strip having substantially parallel ridges extending longitudinally thereof, substantially helically extending shoulder means in said sleeve providing axially spaced shoulders therein, said shoulders being disposed so as to engage edge portions of the strip for holding the same in a position such that said ridges form screw threads, and a weld anchoring one end only of the strip to the sleeve while other portions of the strip remain free and are capable of limited shifting between said shoulders and relative to said sleeve.

8. A thread protector comprising, a first strip of sheet metal having integral lugs thereon and being curved to the form of a sleeve in which said lugs lie in spaced substantially helically extending rows, and a sheet metal insert strip having longitudinal ridges thereon and bein curved to annular shape and retained in said sleeve between said rows of lugs and with its ends in offset relation so that said ridges form screw threads.

9. A thread protector comprising, a first strip of sheet metal having integral lugs thereon and being curved to the form of a sleeve in which said lugs lie in spaced substantially helically extending rows, a weld joining the ends of said first strip, and a sheet metal insert strip having longitudinal ridges thereon and being curved to annular shape and retained in said sleeve between said rows of lugs and with its leading and trailing ends in offset relation so that said ridges form screw threads, said insert strip having its leading end only anchored to said sleeve and said leading end being disposed in the sleeve so as to span the joint formed by said weld.

10. A protector for application to a threaded member comprising, a metal sleeve having axially spaced substantially circumferentially extending shoulders thereon, and an annular metal strip having longitudinal ridges thereon and being disposed between said shoulders and adjacent the wall of said sleeve so that said ridges form screw threads, there being clearance between said strip and said shoulders and the strip being resilient and having one end only anchored to the sleeve While other portions of the strip are unattached REFERENCES crrEIi The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 860,897 Blakey et a1 July 23, 1907 1,893,927 Avery Jan. 10, 1933 

